Abstract: Methods for characterizing radar can include the steps of receiving a plurality of radar emissions, and determining a plurality of Pulse Repetition Intervals (PRIs) corresponding to the emissions. A plurality of clocks Xi can be calculated using the PRIs. A clock range and a clock interval can be defined for the plurality of calculated clocks Xi and a clock X can be estimated, but only for the clocks Xi that are within the defined clock range. Countdowns Ci can be determined using the calculated clock X, and a mode M and crystal b can be calculated based on Ci. Clock X, countdowns Ci, mode M and crystal b, when considered together can accurately characterize a specific radar emission (and radar the emission came from). The systems and methods can be accomplished using emissions that are being received in real time using a receiver and emissions data from a database simultaneously.